A guide bar of the kind described above is provided to guide and support an endless saw chain running around the periphery thereof. The guide bar is releasably attached at one end to the motor-driven chain saw and projects outwardly therefrom for its entire length in the manner of a cantilever. Because of its attachment at one end, the guide bar must take up loading which occurs at its free end such as the high forces occurring in the case of plunge-cutting operations, for example. During such operations, large bending and/or torsion forces can be directed into the guide bar, for example, when the latter jams in the kerf. These loadings are more intense in their effect the longer that the guide bar is. The guide bar must therefore have a high strength which can be obtained by a correspondingly heavy configuration. A heavy guide bar is, however, very disadvantageous in the case of handheld portable motor-driven chain saws because this inevitably makes manipulation of the chain saw more difficult. For this reason, attempts have long been made to reduce the weight of the guide bar.
U.S. Pat. No. 3,545,505 discloses an arrangement for saving weight wherein the guide bar is made up of a plurality of parts such that it has two outer plates made of high-quality steel which are intended to take up the mechanical loading. A center layer made of plastic is provided between both outer steel plates to save weight. Furthermore, it is known in a multi-layered guide bar as shown in U.S. Pat. No. 3,545,505 and in a full guide bar as shown in German Patent No. 728,639 to provide the steel plates with cutouts lying in the plane of the guide bar and to fill these cutouts with a specific lighter material such as plastic or light-weight metal. However, with reference to the practical application, no satisfactory self-rigidity could be obtained and especially a guide bar instability which is too great could be observed especially with professional continuous use which caused guide bars of this kind not to be very successful in the market place.